Abstract: Objective To investigate the treatment and the changes of T lymphocytes before and after transplantation in a child of immunodeficiency-centromeric instability-facial abnormal syndrome type 2 caused by the ZBTB24 gene mutation. Methods The clinical manifestations, laboratory indicators, genetic test results, the process of hematopoietic stem cell transplantation, post-transplantation genetic verification results and follow-up were retrospectively analyzed. T lymphocytes and immunoglobulin before and after transplantation were analyzed by flow cytometry. Results This case is the first child with ICF syndrome type 2 in China to undergo hematopoietic stem cell transplantation. After transplantation, granulocyte engraftment occurred at +11 d and platelet engraftment at +34 d. Laboratory tests at +70 days showed normal expression of IgA, IgG, and IgM. At +177 days, the absolute count of lymphocyte subsets indicated that T lymphocytes had returned to normal. The primary pulmonary infection was controlled, and the viral infection turned negative. No new infections were observed during one-year follow-up. Before transplantation, T lymphocytes count and immunoglobulin expression were significantly decreased, and returned to normal after transplantation. Conclusion The possibility of immunodeficiency caused by gene mutation should be considered for children with recurrent infection at early age, accompanied by facial abnormalities, growth and/or intellectual developmental delay. And timely ICF gene testing should be tested. For those with severe combined immunodeficiency, allogeneic hematopoietic stem cell transplantation should be performed as early as possible.

Key words: ZBTB24 Gene, ICF syndrome, Immunodeficiency-centromeric instability-facial anomalies syndrome type 2, T lymphocyte